There’s an old football adage that explains successful football teams are built from the inside out, and no team has taken this adage to heart as much as the Tennessee Volunteers, especially on the defensive side of the ball.

To translate, the adage is saying that the most successful football teams are the teams that can win at the line of scrimmage on both sides of the ball. The way Tennessee has built its defense in recent years, it appears to be aiming to do just that.

The Vols brought in stud defensive end Derek Barnett last season, and he promptly broke Jadeveon Clowney’s freshman sack record while leading the Vols to their first bowl appearance in five years. This offseason Tennessee added six defensive linemen in its recruiting class, one of which was rated as a five-star prospect and four of which were rated as four-star talents.

Factor in returning edge rusher Curt Maggitt, and you’ve got the makings of one of the SEC’s nastiest defensive lines, which should serve Tennessee well this fall, especially considering the team’s questionable depth in the secondary and lack of a sure starting middle linebacker.

So much of what the defensive line can and cannot do will dictate what opposing offenses can and cannot do. If the line is generating a push up front, opponents will struggle to run the ball between the tackles, forcing them to run laterally rather than downhill toward the line to gain.

And if Barnett, Maggitt and at least one other defensive end can consistently bring pressue in the backfield, it’ll disrupt timing and force predictability into opposing passing offenses.

Here’s an example of the impact a stout defensive line can make on a program: Last season, Tennessee finished third in the SEC in sack total and ninth in rushing defense, resulting in a 7-6 season including its first bowl win since the Phillip Fulmer era.

The season before, Tennessee finished last in the SEC in sack total and second-to-last in run defense, and the result was a 5-7 record. In 2012, Tennessee was once again last in sack total and second from last in rushing defense, and once again UT missed a bowl game with a 5-7 record and just one SEC victory.

To contrast, Missouri has led the SEC in sacks and finished in the top-half of the conference in rushing defense each of the last two years, and the Tigers managed to win the SEC East crown both years despite boasting an offense that ranked as low as 13th in the conference a year ago.

It would be oversimplifying the issue to say UT’s lack of success during those seasons was solely due to its lack of prowess along the defensive line, but that definitely played a major role in the Vols’ follies in those years. It’s certainly no coincidence that as UT began to right its defensive line, the rest of the defense, and team as a whole for that matter, began to follow suit.

With a pass rush in place, the secondary was granted shorter windows in which to maintain coverage, and defensive backs were able to take more chances in coverage because the Vols had a pass rush disrupting timing up front. And if the defensive line is as solid in stopping the run as it’s expected to be when it comes to rushing the passer, that should benefit a linebacking corps that remains relatively unproven aside from Jalen Reeves-Maybin.

In a conference with as many stout rushing attacks as the SEC maintains in 2015, having the ability to generate a push up front on defense means having the ability to turn some potent offenses into predictable, one-dimensional units. UT appears to have the bodies in place to generate that push this fall with the additions of large, talented defensive tackles like Kahlil McKenzie and Shy Tuttle.

Barnett and Maggitt are already proven pass rushers, and that should help newcomers Kyle Phillips, Andrew Butcher and Darrell Taylor establish themselves at the college level sooner than later. Considering Barnett already dictates multiple blockers on most plays while Maggitt warrants extra attention in obvious passing situations, there should be plenty of opportunities for UT’s young talents to effectively rush the passer.

The Vols now have versatility and depth up front, and with Barnett they have a player that forces opposing offenses to adjust their gameplans each week, which gives even more control and confidence to the Tennessee defensive line.

The worst-case scenario in Knoxville is that the Vols 2015 signees are unable to translate to the FBS level as true freshmen, forcing Barnett and Maggitt to carry a heavy burden throughout the season without as much depth or push up the middle from the defensive tackle spots.

But the best-case scenario is at least three or four of the six signees can make some impact as freshmen, aiding Barnett and Maggitt in their efforts to disrupt opposing offenses at the point of attack.

Regardless of how 2015 shapes out, Tennessee is building a defensive line capable of anchoring one of the SEC’s top defenses down the line. Barnett won’t be NFL eligible until after the 2016 season, and he’ll have the opportunity to return to Knoxville and play in 2017 as well. The Volunteers’ 2015 signees won’t be NFL-eligible until after 2017, and they’ll have the chance to return for the 2018 season and perhaps even 2019 depending on who claims a redshirt seasons in the coming years.

Tennessee has talent and depth on defense, but it also has youth and the foundation for a strong defensive line not just this year but for the next handful of years as well. If winning football is indeed built from the inside out, Tennessee is making all the right moves to build a winning program in the SEC for years to come.

It remains to be seen how the Vols’ new talents will turn out in the SEC, but on paper Tennessee has formed one of the conference’s best defensive lines, which should help lead UT to its best season in nearly a decade.